Dear all,
Please see attached pic of human total RNA analyzed by Fragment analyzer, the 28s rRNA peak is somehow missing (blue peak), any idea? it seems not degraded...
Thank you for you help.

Insects frequently have this total RNA profile due to a cleavage site in the large sub unit ribosomal RNA. Drosophila, for instance, has the cleavage site situated such that the two fragments migrate right on top of the small sub unit ribosomal RNA.

Don't think I've seen that phenomenon in human RNA, though.

Although, if the cleavage were tissue specific, then one might not run into it in most human RNA preps.